#include <stdio.h>

char *mystrstr(const char *dest, const char *src)
{
    if(*src == '\0')
    {
        return dest;
    }

    const char *d;
    const char *s;

    while(*dest != '\0')
    {   
        d = dest;
        s = src;

        while(*dest != '\0' && *src != '\0' && *dest == *src)
        {
            d++;
            s++;
        }

        if(*src == '\0')
        {
            return dest;
        }

        if(*dest == '\0')
        {
            break;
        }

        dest++;
    }

}